Bottom hole burner



Jan. 17, 1967 w. A. REES, JR

BOTTOM HOLE BURNER Filed July 29, 1964 w ql I \\\\\\\\\\\\-\\\u r 5 Z1 5 7 5 3 5 z w 4 5 w v I m a Q f 5 N V 5 3 3 a W 7 6 9 a 0 7 J 0 V A I {I 5 Q 3 K x mw 5 9 1. 4 W 7 .Q@ T w MW 6 United States Patent 3,298,439 BOTTOM HOLE BURNER Warren A. Rees, Jr., Corpus Christi, Tex., asssignor to Tgxaco Inc., New York, N.Y., a corporation of Delaw re Filed July 29,1964, Ser. No. 385,898 7 Claims. (Cl. 16659) The present invention relates to a burner for introducing heat into an oil well, particularly for initiating an in situ combustion operation in an injection well to drive oil through an earth formaton to nearby production wells.

Burners for use in oil wells are well known, and a number of patents have been issued covering various designs. However, the burners of the prior art are subject to certain disadvantages which are overcome by my novel burner construction. One type of burner disclosed in US. Patent 2,668,592 has a combustion Zone with a bottom outlet which is always open. This type of burner is not employable in wells which contain liquids at the point of heating because the liquid tends to enter the combustion zone and prevent ignition of the combustible gases therein. A burner which would not be subject to this disadvantage is shown in US. Patent 1,626,940, but this burner relies wholly upon indirect heat transfer to the formation fluids because the bottom of the combustion chamber is permanently closed so that the gases of combustion are carried back up to the surface of the earththrough an auxiliary conduit associated with the burner.

Burners of the prior art also lack means for measuring temperatures at various points within a well so as to determine whether or not combustion is proceeding efliciently. Moreover, they are not adequately constructed adjacent the surface of the earth for assuring maintenance of a high gas pressure within the well, while at the same time permitting movement of the burner up or down in the well for extending the heating operation over the full length of a producing zone.

My burner will overcome the disadvantages of the prior art discussed above and assure satisfactory burning of a combustible gas mixture within a well at great depths, whether or not the well is partially full of liquids at the start of the operation.

In its broader aspects my bottom hole burner for introducing heat into an oil well comprises a combustion chamber having an upper end and a lower end, a first conduit secured to the top of the combustion chamber and extending upwardly therefrom to the surface of the earth, and a second conduit within the first conduit opening into the combustion chamber and extending upwardly therefrom to a terminal position intermediate the ends of the first conduit. One of the conduits is a fuel gas conduit and the other is for a combustion-supporting gas, the two gases being delivered separately to the combustion chamber and mixed therein to form a combustible gas mixture.

A seal in the space between the first and second conduits near the terminal end prevents passage of gas around the second conduit while permitting gas to enter it. The first conduit has apertures below the seal for permitting the access of another gas from outside the conduit into the space between the first and second conduits. A sleeve surrounding the first conduit has an open lower end for delivering a large volume of air, and an upper end controlled by a valve for receiving air.

An igniting device is positioned in the upper end of the combustion chamber for igniting the combustible mixture, preferably being an electrical spark producing device or a high resistance electrical heating wire. Alternatively the ignitor can comprise a spontaneously combustible chemical device which will be described more in detail hereinafter.

In order to prevent the access of well liquids into the combustion chamber, its lower end is closed by a plug which is so constructed and arranged as to engage the walls of the combustion chamber when a low pressure exists therein, but to be blown away from the chamber when a predetermined higher gas pressure is developed therein.

The upper end of the burner, including the design for maintaining a pressure tight seal at the well head while the various gases and electrical currents are passed from outside the well head into the burner, essentially is described in my copending application Ser. No.'385,893, filed concurrently herewith. The well head also is so constructed that a gas, such as air or nitrogen, can be supplied thereto for passage down through the well on the outside of the burner for expelling liquids from the well into the formation, as well as for sustaining in situ combustion of oil in the formation surrounding the well.

The well head is so designed that the burner can be raised or lowered in the well without destroying the pressure tight seal at the surface of the earth.

When operating my burner to introduce heat into a well which contains a pool of liquid at the point where heating is desired, the burner is introduced from the surface of the earth into the well and its lower end containing the combustion chamber is submerged in the pool of liquid which is prevented from entering the burner by the plug which provides a temporary seal in the flame outlet of the burner. Then a gas such as air, nitrogen or natural gas is introduced into the well on the outside of the burner under sufficient pressure to drive the liquid into the earth formation and leave the burner free. Then a gas such as air is introduced into the burner under sufficient pressure to blow the plug away from the flame outlet. At that time a combustible mixture is formed in the combustion chamber of the burner by providing separate streams of air and fuel gas which mix within the chamber, and this mixture is ignited to form a flame by inducing a spark or other source of high temperature heat and the hot gases of combustion are discharged from the combustion chamber into the well through the flame outi let. If desired, a flowing stream of air or other combustion-supporting gas can be concurrently introduced into the well on the outside of the burner, this being especially desirable after in situ combustion of the oil in the surrounding formation has been initiated as the combustionsupporting gas will then promote the in situ combustion.

The invention will be described more in detail in connection with the accompanying drawings, wherein:

FIG. 1 is a vertical sectional view, parts being in elevation, of a burner embodying the novel features of the invention, and

FIG. 2 is a cross sectional View taken along the line 2-2 in FIG. 1.

Referring to FIG. 1, the lower end of a burner B comprises a cylindrical combustion chamber 11 which is formed of heat resistant metal such as steel, with or without a refractory ceramic lining, and has a flame outlet13 at its lower end which is closed by a blowout plug 15 frictionally fitted into the chamber Chamber 11 can be any suitable length, e.g. ranging from as short as 6 inches to as long as 6 feet. Plug 15 can be formed of any suitable material, but it is preferably a plastic material such as polyethylene which will burn and be destroyed in the well after it is blown out and the flame impinges thereon.

The upper end of chamber 11 is frusto-conical in shape and merges into a conduit 17 of considerably smaller diameter than the chamber for conducting air thereto. There also opens into the upper end of the combustion chamber a central conduit 19 for fuel which is annularly spaced within conduit 17 and projects down below the lower end thereof.

Conduit 19 extends upwardly and opens at its upper end into an upper portion of conduit 17, and a packer 21 is provided in the annulus 22 adjacent the upper end so that fuel gas can pass down through conduit 17, and into conduit 19 without entering annulus 22.

Conduit 17 extends upwardly in the well and passes through a well head W at the surface of the earth in pressure tight relationship thereto so as to prevent the escape of gases out of the hole, and to permit the injection of gas for combustion purposes.

Air is introduced into the annulus 22 through a plurality of apertures 23 in the wall of conduit 11 below the packer 21, with the air being pumped from the surface of the earth through the well head and into the annulus 25 surrounding the burner and within a casing C (or the wall of the well where no casing is used). A packer 27 is located in the space between a sleeve 29 and the casing C. Sleeve 29 is concentric with conduits 17 and 19, extends from a position between packer 27 and apertures 23 down to a position spaced above combustion chamber 11, and is open at its lower end for the flow of air therethrough.

Sleeve 29 is held in place by four circumferentially equi-spaced radial legs (two shown in elevation) constituting a spider 31 which is secured to the conduit 17 and sleeve 29 in the annular space 32 therebetween.

The open top of sleeve 29 is closed by a valve disc 33 having a bevelled periphery, which is threadedly mounted on conduit 17 for movement up or down as the conduit is rotated while the valve is held against rotation by a plurality of slides 35 riding in longitudinal grooves 37 in the internal wall of the sleeve. Conduit 17 can be rotated by a conventional turn-table or wrench at the surface of the earth.

A swivel 39 connects together upper and lower parts of the conduit 17 so as to permit the upper part to rotate while the lower part and combustion chamber 11 are held stationary by a plurality of spring steel spacers 41 projecting radially from the chamber 11, and 43 projecting radially from sleeve 29.

Also afliliated with the combustion chamber 11 is a spark plug 45 which extends in pressure tight relationship through a packing gland 47 in the frusto-conical wall of the chamber and has a single electrode 49 positioned in slightly spaced relationship to the end of the metal conduit 19 so as to produce a spark therebetween when energized. A conductor wire 50 extends upwardly from spark plug 45 through annulus 32, out through a packing gland 51 in the side wall of sleeve 29 above packer 27 and thence to the surface of the earth through annulus 25.

Additionally, several thermocouples (not shown) are carried on the outside of the combustion chamber for measuring the temperature at various points within the well. All of these thermocouples are connected by a suitable electrically conductive multi-conductor cable 53 up through sleeve 29, through a packing gland 55 in the wall of the sleeve, and thence to recording devices at the surface of the earth.

Now referring to the well head W, the casing C is held by a conventional casing clamp 61 which lies on the surface 63 of a platform or the earth. Clamp 61 comprises a pair of mating half cylinders having flanges bolted together. A sleeve 65 having a pair of inlets 67 and 69 for a gas such as air is threaded over the upper end of the casing C and abuts against the casing clamp 61 so that air may be introduced into the casing and flow downwardly therethrough in the annular space surrounding the burner.

On the top of sleeve 65 there is secured a well head collar 71 provided with appropriate pressure sealing packers 73 and 75 for engaging a lubricator pipe 77 which is adapted to move upwardly and downwardly through the well head while maintaining a pressure tight seal. The top of collar 71 is closed by a cap 79 threaded over the collar and bearing against a gasket 81.

The upper portion of lubricator pipe 77 includes a joint formed by a pair of flanges 83 and terminates in an enlarged frusto-conical and then cylindrical section 85 having an open top which is closed by a cap 87 resting on a circular gasket 89.

A pair of radially extending ears 91 on the cap are connected to the casing clamp 61 by a pair of cables 93 maintained in tension by turnbuckles or other device 95 for assuring pressure tightness, and also for providing a means for forcing the lubricator pipe downwardly through the well head when movement of the burner at the sand face is desired, and also for preventing the burner and associated pipe from blowing out of the well under high pressure therein.

The top of cap 79 is provided with appropriate packing glands 97, 99, and 191 for the high tension spark wire 50, the fuel pipe 17, and the thermocouple multiconductor cable 53, respectively, all of which are connected to suitable sources of supply of the appropriate gases and electrical currents, or to temperature recording devices on the outside of the well. Ignition can be accomplished by an automotive type ignition system.

Appropriate control valves and switches are provided in the various supply lines for gases and electricity, respectively.

The described construction has the advantage of completely eliminating the need for a separate air conduit because all air is conducted down the space between the burner and the casing.

In the preferred method of operating the burner described in detail above, it is lowered into the hole until the combustion chamber 11 is opposite the formation to be treated, after which a large supply of high pressure gas such as air or nitrogen is introduced through the well head into annulus 25 and then into sleeve 29 (valve disc 33 being raised) to force the pool of formation liquids out into the porous formation surrounding the well. The liquids pass out through apertures (not shown) in casing C opposite the producing formation when the well is cased. After the well has been freed of liquid, the upper part of conduit 17 is rotated while combustion chamber 11 is held stationary to cause valve disc 33 to move down and close the top of sleeve 29. Air then enters ape-rtures 23 and blows out plug 15.

Then the flow of fuel gas such as natural gas into the top of conduit 17 and thence through the conduit 19 is commenced to mix in chamber 11 with the air to form a combustible mixture. An airzfuel ratio greater than 10:1 is desirable. At this time a high tension electrical current is supplied to the electrode 49 and arcs across to the fuel conduit 19 to ignite the combustible gas mixture and create a high temperature flame which extends downwardly through the chamber 11 and the outlet 13 to the interior of the well. The hot gases of combustion pass outwardly through the apertures in casing C and into the formation, eventually heating the formation hydrocarbon material to a temperature at which in situ combustion develops and a flame front is created which extends outwardly from this injection well to force formation liquids to a producing well nearby. At this time conduit 17 is rotated to raise valve disc 33 and the flow of air is increased so that air passes not only into the combustion chamber but also down through sleeve 29 to support in situ combustion.

As in known oil field practice, as the burner is lowered additional joints of pipe are connected together to create the long pipes which may be several hundred feet long. During lowering the thermocouple wires and ignition wire are strapped to the pipes. When the burner reaches the formation the various supply lines are threaded through lubricator 77', flanged joint 83, chamber 85 and cap 87. The whole unit is 11161 owered so that lubricator pipe 77 can be hung in the slips of the well head. If the burner is not to be moved in operation, the lubricator pipe can be attached directly to the collar 71. The flanged joint 83 is then made up and the installation is complete.

Instead of a spark gap for ignition, a high resistance glow wire can extend from the ignitor 45 to direct contact with the fuel conduit 19, or to another electrically conductive part of the burner, to form a glowing hot wire.

Still another means for igniting the combustible gas mixture involves the provision of a liquid absorbent cotton wick suspended within the upper portion of the combustion chamber 11, and the injection through the conduit 17 of a spontaneously ignitable liquid such as linseed oil containing a catalyst and promoter, for example cobalt naphthenate and dimethyl aniline. The flow of air through apertures 23'and annulus 22 is inauguarted and causes the wick and the absorbed fluid to ignite spontaneously and ignite the combustible gas mixture.

The method and the apparatus described above are particularly applicable to the initiation of in situ combustion operations in oil bearing formations. However, the burner also can be used for the elimination of formation restrictions, (1) caused by naturally occurring fluids, extraneous fluids or combinations of the two; (2) caused by liquids or solids deposited from drilling fluids; (3) caused by dehydratable or oxidatable substances occurring naturally in the formation; (4) caused by extraneous substances placed in the well bore or formation including cement, plastics, gelled liquids and other chemicals used in the drilling completion or treatment of a well.

It is useful for any other operation or procedure where the application of heat to the well bore formations, or substances in the vicinity of the well bore, or the equipment or substances within the well bore is advantageous, e.g., consolidating sand 'by warm air coking.

Where initiation of in situ combustion is not an object, then nitrogen can 'be sent down the casing to help eliminate restrictions.

Obviously, other modifications and variations of the invention, .as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. A bottom hole burner for introducing heat into an oil well comprising, in combination, a combustion chamber;

a first conduit secured to the top of said combustion chamber and adapted to extend upwardly therefrom to the surface of the earth;

a second conduit within said first conduit opening into said combustion chamber and extending upwardly therefrom to a terminal position intermediate the ends of said first conduit;

means sealing the space between said first and second conduits adjacent said terminal position;

said first conduit having apertures through the wall thereof below the sealing means to permit the access of gas from outside said conduit into the space between said first and second conduits;

a sleeve surrounding said first conduit in annularly spaced relation thereto and extending from a position below said apertures downwardly to a position spaced above said combustion chamber;

a valve carried by said first conduit sealing the space between said first conduit and said sleeve adjacent the upper end of said sleeve, said valve being mov able upwarly and downwardly into and out of sealing relationship with the top of said sleeve whereby gas flow from the space surrounding said first conduit into said sleeve can be controlled; and

an ignitor means positioned in said combustion chamber for igniting a combustible mixture therein.

2. A bottom hole burner in accordance with claim 1 also comprising a packer carried on the outside of said sleeve for sealing the annular space surrounding said sleeve when said burner is in a well.

3. A bottom hole burner in accordance with claim 1 wherein said valve is threaded on the outside of said first conduit and includes means for preventing rotation thereof when said first conduit is rotated whereby rotation of said first conduit causes said valve to move upwardly or downwardly in accordance with the direction of rotation.

4. A bottom hole burner in accordance with claim 3 wherein said means for preventing rotation of said valve comprises a plurality of grooves in the internal wall of said sleeve, and a plurality of bosses carried by said valve and located in said grooves for movement upwardly and downwardly therein.

5. A bottom hole burner in accordance with claim 3 wherein said first and second conduits include a coupling below said valve and so constructed and arranged that when the portion of said first and second conduits above said coupling is rotated the portion below said coupling remains stationary.

6. A bottom hole burner in accordance with claim 5 also comprising means connecting together said first conduit and 'said sleeve for retaining said members in annularly spaced relationship to one another while permitting the flow of fluid in the annulus therebetween.

7. A bottom hole burner in accordance with claim 3 also comprising means carried on the outside of said sleeve engaging an adjacent wall and spacing said sleeve therefrom;

and means on the outside of said combustion chamber for also engaging said adjacent wall to space said combustion chamber therefrom.

References Cited by the Examiner UNITED STATES PATENTS 2,225,775 12/1940 Garrett 166-57 X 2,584,606 2/1952 Merriam et al. 166-59 X 2,725,929 12/1955 Massier 158-28 2,985,240 5/1961 Emery 166-59 3,223,165 12/1965 Hujsak 166-38 3,254,721 6/1966 Smith 166-59 CHARLES E. OCONNELL, Primary Examiner, D. H. BROWN, Assistant Examine), 

1. A BOTTOM HOLE BURNER FOR INTRODUCING HEAT INTO AN OIL WELL COMPRISING, IN COMBINATION, A COMBUSTION CHAMBER; A FIRST CONDUIT SECURED TO THE TOP OF SAID COMBUSTION CHAMBER AND ADAPTED TO EXTEND UPWARDLY THEREFROM TO THE SURFACE OF THE EARTH; A SECOND CONDUIT WITHIN SAID FIRST CONDUIT OPENING INTO SAID COMBUSTION CHAMBER AND EXTENDING UPWARDLY THEREFROM TO A TERMINAL POSITION INTERMEDIATE THE ENDS OF SAID FIRST CONDUIT; MEANS SEALING THE SPACE BETWEEN SAID FIRST AND SECOND CONDUITS ADJACENT SAID TERMINAL POSITION; SAID FIRST CONDUIT HAVING APERTURES THROUGH THE WALL THEREOF BELOW THE SEALING MEANS TO PERMIT THE ACCESS OF GAS FROM OUTSIDE SAID CONDUIT INTO THE SPACE BETWEEN SAID FIRST AND SECOND CONDUITS; A SLEEVE SURROUNDING SAID FIRST CONDUIT IN ANNULARLY SPACED RELATION THERETO AND EXTENDING FROM A POSITION BELOW SAID APERTURES DOWNWARDLY TO A POSITION SPACED ABOVE SAID COMBUSTION CHAMBER; A VALVE CARRIED BY SAID FIRST CONDUIT SEALING THE SPACE BETWEEN SAID FIRST CONDUIT AND SAID SLEEVE ADJACENT THE UPPER END OF SAID SLEEVE, SAID VALVE BEING MOVABLE UPWARDLY AND DOWNWARDLY INTO AND OUT OF SEALING RELATIONSHIP WITH THE TOP OF SAID SLEEVE WHEREBY GAS FLOW FROM THE SPACE SURROUNDING SAID FIRST CONDUIT INTO SAID SLEEVE CAN BE CONTROLLED; AND AN IGNITOR MEANS POSITIONED IN SAID COMBUSTION CHAMBER FOR IGNITING A COMBUSTIBLE MIXTURE THEREIN. 